72 C10 heater/ A/c wiring diagram - The 1947 - Present Chevrolet & GMC Truck Message Board Network

kevmo707 · 07-13-2012, 09:17 PM

I need a wiring diagram for the heater/ A/C for my 1972 C10. The blower motor only works on low and medium but not high. Mostly all the parts are new in the system so I think it is in the wiring.

Thanks

oklalawnboy · 07-14-2012, 12:04 AM

Quote:

Originally Posted by kevmo707

I need a wiring diagram for the heater/ A/C for my 1972 C10. The blower motor only works on low and medium but not high. Mostly all the parts are new in the system so I think it is in the wiring.

Thanks

in the past when I had that problem, it was either the switch or high blower relay. Just throwing out some ideas
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kevmo707 · 07-14-2012, 02:32 PM

Thanks Ill check them... where is the relay for the high setting???

Daddy'O · 07-14-2012, 02:43 PM

Most likely the relay - This link to another thread should help out.

http://67-72chevytrucks.com/vboard/s...=a%2Fc+diagram

Good luck!

oklalawnboy · 07-14-2012, 11:21 PM

Mine is mounted/attached to the heater box under the dash behind the glove box. To the right side looking through the glove box door.

KellerMAC · 07-15-2012, 11:12 AM

Just rebuilt my factory AC and here is what I found - I had the opposite problem than you - my low and med speeds weren't working but high was. The high side is your relay and it is mounted to the heater box behind the glove box. The low and med speeds are resistor related. The resistor is located inside the heater box under the dash. You will need to remove the plenum and air selector to access the resistor. I took mine out and cleaned it up and then replugged it in before I reinstalled it and tested it. I got lucky, it worked.

Good Luck

07-13-2012, 09:17 PM	#1
kevmo707 Registered User Join Date: Oct 2011 Location: Scottsdale Az Posts: 5	72 C10 heater/ A/c wiring diagram I need a wiring diagram for the heater/ A/C for my 1972 C10. The blower motor only works on low and medium but not high. Mostly all the parts are new in the system so I think it is in the wiring. Thanks

07-14-2012, 02:32 PM	#3
kevmo707 Registered User Join Date: Oct 2011 Location: Scottsdale Az Posts: 5	Re: 72 C10 heater/ A/c wiring diagram Thanks Ill check them... where is the relay for the high setting???

07-14-2012, 02:43 PM	#4
Daddy'O Registered User Join Date: Jan 2012 Location: Whitesboro, Texas Posts: 932	Re: 72 C10 heater/ A/c wiring diagram Most likely the relay - This link to another thread should help out. http://67-72chevytrucks.com/vboard/s...=a%2Fc+diagram Good luck! __________________ Cheers - Wayne Our Shop Build - http://67-72chevytrucks.com/vboard/s...d.php?t=620966 '55 Wagon Build - http://67-72chevytrucks.com/vboard/s...d.php?t=689157 1971 Cheyenne Super Ochre/White LWB 350 Auto - my son's truck "Nancy" 1972 GMC K2500 Custom 4X4 Olive LWB 400 SB 4-speed -"Greenie" - Restoration to begin after the '55 Nothing sucks more than that moment during an argument when you realize you're wrong.

07-14-2012, 11:21 PM	#5
oklalawnboy Registered User Join Date: Jan 2012 Location: Glencoe Alabama Posts: 510	Re: 72 C10 heater/ A/c wiring diagram Mine is mounted/attached to the heater box under the dash behind the glove box. To the right side looking through the glove box door. __________________ 72 Cheyenne super 10 08 3500 HD 4dr dually 12 ford flex (wifes ride) 76 Monte Carlo 83 Chevy short wide Silverado 96 Mazda Miata, 2000 Allegro Bus

07-15-2012, 11:12 AM	#6
KellerMAC Registered User Join Date: Jan 2007 Location: Keller, TX Posts: 143	Re: 72 C10 heater/ A/c wiring diagram Just rebuilt my factory AC and here is what I found - I had the opposite problem than you - my low and med speeds weren't working but high was. The high side is your relay and it is mounted to the heater box behind the glove box. The low and med speeds are resistor related. The resistor is located inside the heater box under the dash. You will need to remove the plenum and air selector to access the resistor. I took mine out and cleaned it up and then replugged it in before I reinstalled it and tested it. I got lucky, it worked. Good Luck __________________ Texas - Don't Let The Size Scare You!



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